Loose-spring piston-packing expander.



G. GHRISTENSON. LOOSE SPRING PISTON PACKING EXPANDER. APPLICATION FILEDJULY 26, 1911.

1 ,023 ,8 1 3 Patented Apr. 23, 1912.

' UNITED STATES PATENT OFFICE.

GEORGE CHRISTENSON, OF NEW YORK, N. Y., ASSIGNOR TO H. W. JOIINS-MANVILLE COMPANY, A CORPORATION OF NEW YORK.

LOOSE-SPRING PISTON-PACKING EXPANDER.

To all whom it may concern:

Be it known that I, GEORGE CHRIsTENsoN, a citizen of the United Statesof America, residing at Jamaica, city of New York, county of Queens,State of New York, have invented certain new and useful Improvements inLoose-Spring Piston-Packing Expanders, of which the following is aspecification.

My invention relates to packing expanders for pistons and comprises animprovement on apparatus shown and described in Patent No. 984,888granted February 21, 1911, upon my application. In the special form ofpis ton packing expander contemplated. in said patent, and heretoforemanufactured thereunder, the envelop of thin sheet metal surrounding thespring metal ring, which gives the structure elasticity, has alwaysfitted so tightly to the said ring as to render any slipping of one overthe other impossible. The two portions,ring and envelophave been fixedrelatively one to the other, the spring ring being completely covered bythe sheet metal ring, and the point or abutting ends of the two portionsof the structure being located at approximately the same point in thecircle, and fixed in that location. Certain disadvantages have resultedfrom this feature of construction, as follows: With the form of expanderring shown in my said patent, and in all other forms of packing expanderrings so far known to me, it has been possible by roughly handling thesame to produce a distortion of form such as will produce a permanentset in the elastic materials composing the ring and result in theabutting ends not exactly meeting when the ring is placed in positionfor use, or in otherwise preventing the structure from as suming theform of a perfect circle which is necessary in order to make a perfectpiston packing expander. I have discovered that by reversing thearrangement of the spring ring and sheet metal envelop therefor employedin composite expander rings so that the two will break oints and givingone a loose sliding fit in the other, the maintenance of shape of thecomplete ring in use is assured no matter what its previous handling hadbeen.

The best form of apparatus embodying my invention at present known to meis illustrated in the accompanying sheet of drawings, in which,

Specification of Letters Patent.

Application filed July 26, 1911.

Patented Apr. 23, 1912.

Serial No. 640,584.

Figure 1 is a plan view of an apparatus embodying my invention withparts broken away, the ring being shown in expanded position. Fig. 2 isa similar view with the ring being sprung into the position which itapproximates in use. Fig. 3 is a detail view of one form of abuttingends for the outer envelop of the ring and Fig. 4 is an enlarged crosssection on line 4.-4: of Fig. 3.

Throughout the drawings like reference characters indicate like parts.

5 is a ring of highly tempered steel or highly elastic material,preferably of circular cross section which may be formed by cutting therequired length from a steel rod of the proper size and bending the sameinto ring form with the ends slightly separated.

6 is a strip of thin sheet material such as mild steel cut from anordinary sheet of such material, and also bent into ring shaped formwith the ends separated by a distance equal to that which separates theends of the ring 5. This strip 6 is loosely attached to the ring 5 inany convenient way, as by curling one edge of the strip 6 around thering 5, as best shown in Fig. 4. This curled portion of the strip 6forming the outer envelop is given an internal diameter such that thering 5 has a loose sliding fit therein, and this envelop 4 and ring 5are arranged as shown in Fig. 1 so as to break joints, the ends 7, 7, ofthe elastic ring 5 coming at one side of the ring within the envelop andthe abutting ends 8, 8, of the strip 6 coming at the other side of thering. WVhen the diameter of the composite ring so produced is reduced,as by external pressure the ends of the spring 5 and strip 6 meet, asshown in Fig. 2, but Whenever the pressure is released the ring tends tospring back into the position shown in Fig. 1. The abutting ends ofstrip 6 may be given any mutually corresponding shape to produce acomplete closure when they are forced together, but I prefer to havethem cut on lines 9, 9, which are parallel and lines 10, 10, which areat right angles to the circumference of the ring, as shown in Fig. 3, soas to form mutually overlapping portions.

In use the main body of the strip 6 which is arranged at right angles tothe plane of the ring is forced against the interior of the usual cupleather packing by the expansion of the spring ring 5. The parts are sode- 116 signed that the mutually overlapping portions of the abuttingends of the strip 6 will never be entirely separated in use andconsequently no portion of the packing will. be devoid of full springpressure.

The advantages of my invention comprise the beneficial action of thespring ring 5 telescoping into the curved portions of the abutting endsof the strip 6 forming its envelop, so that no matter how far apart saidends are pulled by rough handling, they will always be maintained inperfect alinement and upon compression of the ring as a whole will meetagain to form a perfect ring, and also the fact that the maintenance ofsuch perfect alinement permits the shaping of the abutting ends of thestrip 6 to form mutually overlapping portions, as shown in Fig. 3without the danger of said overlapping portions getting one behind theother, and thereby interfering with the free action of the ring in useand forming a slight inequality in the surface of the ring, which willleave a portion of the packing free from full spring pressure andthereby tend to produce leaks.

Of course other means of producing the loose attachment of the springring to the sheet metal strip might be substituted for that shown andother forms of ring and strip employed without departing from theprinciple of my invention. The relative arrangement of the ring 5 andits envelop 4 might also be varied so long as the two break joints, butthe best results and the most efi cient spring action are secured by thearrangement shown in Figs. 1 and 2.

When the spring ring and its loosely fitting envelop are arranged tobreak joints the expansive force of the spring ring is transmittedevenly to every point of the envelop, and an equal outward pressure isdeveloped radially of the ring at every point of the entirecircumference, while in the old form of ring out at one point in thecircumference, different radial pressures develop at different pointsand uneven wear of the packing leather results.

Having, therefore, described my invention, I claim:

1. A piston packing expander having in combination a ring of elasticmetal and a thin strip of sheet material loosely fastened to the ringand forming a flange thereon, extending at right angles to the plane ofthe r111 2 A piston packing expander having in combination a ring ofelastic metal and a thin strip of sheet material loosely wrapped aroundthe ring and projecting at right angles to the plane of the ring to forma flange thereon.

3. A composite piston packing expander formed of a ring of steel of hightemper, and a strip of sheet metal of low temper and high ductilityloosely fastened to the ring and forming a flange thereon, extending atright angles to the plane of the ring.

4:. A composite piston packing expander formed of a ring of steel ofhigh temper, and a strip of sheet metal of low temper and high ductilityloosely bent around the ring and projecting at right angles to the planeof the ring to form a flange from the outer side of the ring.

5. A piston packing expander comprising in combination a ring of hi 'hlyelastic material having abutting en s, and a ring shaped hollow envelopfor said ring, also having abutting ends, the ring and its envelop beingarranged to break j oints.

6. A piston packing expander comprising in combination a ring of highlyelastic material having abutting ends, and a ring shaped hollow envelopfor said ring, also having abutting ends, the ring and its envelop beingarranged to break joints, said envelop being provided with a thinprojectin flange.

?. A piston packing expander comprising in combination a ring of highlyelastic material having abutting ends, and a ring shaped hollow envelopfor said ring, also having abutting ends, the ring and its envelop beingarranged to break joints, said envelop being provided with a thin flangeprojecting at right angles to the body of the ring and from the outsidethereof.

8. A piston packing expander having in combination a ring of highlyelastic material with abutting ends, a strip of thin ma terial also bentinto a ring with abutting ends and having one edge loosely attached tothe first mentioned ring, the two rings being arranged to break joints.

9. A piston packing expander having in combination a ring of highlyelastic material with abutting ends, a strip of thin material also bentinto a ring with abutting ends and having one edge loosely curled aroundthe first mentioned ring, the two rings being arranged to break joints.

10. A piston packing expander having in combination a ring of highlyelastic material with abutting ends, a strip of thin material also bentinto a ring with abutting ends and having one edge loosely curled aroundthe first mentioned ring, the two rings being arranged to break jointsthe main portion of the strip being arranged at right angles to theplane of the ring.

11. A piston packing expander having in combination a ring of highlyelastic material with abutting ends, a strip of thin material also bentinto a ring with abutting ends and having one edge loosely attached tothe first mentioned ring, the two rings being arranged to break joints,the abutting ends of the strip being cut away to form mutuallyoverlapping portions.

12. A piston packing expander having in parallel or at right angles tothe circumfercombination a ring of highly elastic inaence of the ring toform mutually over- 10 terial uiitlll algptting ends, a strip of thinlapping portions. materia a so ent into a ring Wit-1 abutting ends andhaving one edge loosely curled GEORGE CHRISTENSON' around the firstmentioned ring, the two Witnesses: rings being arranged to break joints,the A. PARKER-SMITH, abutting ends of the strip being cut on lines M. G.CRAWFORD.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

